Impact tool attachment for an electric drill



Jan. 27, 1970 D. c. M INTIRE 3,491,339

IMPACT TOOL ATTACHMENT FOR AN ELECTRIC DRILL Original Filed March 27,, 1967 I 27 E 23 2/ /9 7 1: L6

l5 I 4 /9 29 7 J V x 1 29 39 /7 I I 3/ 3 36 3 as l 39 g as //Vl//V7'0A United States Patent C 3,491,839 IMPACT TOOL ATTACHMENT FOR AN ELECTRIC DRILL Daryl C. McIntire, Seymour, Iowa 52590 Continuation of application Ser. No. 626,241, Mar. 27, 1967. This application Feb. 24, 1969, Ser. No. 805,963 Int. Cl. B25d 15/00 U.S. Cl. 17393.6 3 Claims ABSTRACT OF THE DISCLOSURE An impact tool attachment for an electric drill comprising, a first drive shaft adapted to be secured at one end to the drill chuck for rotation therewith, a second drive shaft having a tool means at one end thereof, and an impact clutch means operatively interconnecting said other ends of the first and second drive shafts.

This application is a continuation of SN. 626,241, filed Mar. 27, 1967, now abandoned.

Impact wrenches of various designs are designed only for one use, that is, for removing or securing a nut means. These impact tools are extremely expensive and are not versatile in that they cannot be used for any purpose other than the tightening or loosening of nuts.

Therefore, it is a principal object of this invention to provide an impact tool attachment for an electric drill.

A further object of this invention is to provide an impact tool attachment for an electric drill which is adapted for various mechanical operations.

A further object of this invention is to provide an impact tool attachment for an electric drill which is detachably secured thereto and which may be removed therefrom during periods of non use to permit the drill to be used for other purposes.

A further object of this invention is to provide an impact tool attachment having an impact clutch means operatively interconnecting the tool attachment and the electric drill.

A further object of this invention is to provide an impact tool attachment for an electric drill having adjustable means thereon to permit slippage between a pair of opposing clutch plates when a predetermined torque is achieved.

A further object of this invention is to provide an impact tool attachment for an electric drill which may be utilized whether the drill is of the reversible or variable speed type.

A further object of this invention is to provide an impact tool attachment for an electric drill which is economical of manufacture, durable in use and refined in appearance.

These and other objects will be apparent to those skilled in the art.

This invention consists in the construction, arrangements, and combination of the various parts of the device, whereby the objects contemplated are attained as hereinafter more fully set forth, specifically pointed out in the claims, and illustrated in the accompanying drawings in which:

FIG. 1 is an exploded perspective view of the attachment and the electric drill;

FIG. 2 is a sectional view of the attachment illustrating the opposing clutch plates in a driving relationship;

FIG. 3 is a sectional view similar to FIG. 2 except that the clutch plates are in a slipping condition with respect to each other; and

FIG. 4 is a perspective view of the clutch plates.

The numeral generally designates a conventional electric drill which may be of the reversible or variable speed type. Drill 10 includes a rotatable chuck 11 which is adapted to detachably receive a drive shaft 13 therein. Drive shaft 13 is secured at its upper end to chuck 11 and is adapted for rotation therewith. A drive clutch plate 15 is secured to the lower end of shaft 13 by any convenient means such as welding or the like and has a plurality of equally spaced apart openings 17 formed therein which are each adapted to receive a ball 19 therein. A pressure plate 21 is mounted on shaft 13 above plate 15 and has a collar 23 Welded to the upper surface thereof. A self-locking adjusting nut 25 is threadably mounted on shaft 13 above collar 23 and a spring means 27 embraces shaft 13 between nut 25 and collar 23. Nut 25 may be threadably moved with respect to shaft 13 to adjust the amount of tension that spring means 27 Will exert on pressure plate 21.

A hollow sleeve 29 is secured at its upper end to the periphery of pressure plate 21 by welding or the like and has a supporting plate 31 secured to its lower end by welding or the like. A drive shaft 33 is rotatably mounted in and extends downwardly through plate 31 and has its lower end adapted to detachably receive a tool means such as a socket member 35. A collar means 36 is welded to the lower surface of plate 31 and has a bearing means 37 mounted therein which embraces shaft 33 to permit the rotation of shaft 33 with respect to plate 31 and to lend support and stability to shaft 33. Bearing means 37 is maintained within collar means 36 by set screw 38.

A drive clutch plate 39 is secured to the upper end of shaft 33 by welding or the like between plates 31 and 15 and has a plurality of spaced apart recesses 41 formed in the upper surface thereof which are adapted to receive a portion of balls 19 therein. The tool means which is secured to the lower end of shaft 33 has been shown to be a socket member 35 for this example but it is obvious that socket member 35 could be replaced by any suitable tool means such as a screw driver, etc.

In operation, drive shaft 13 would be mounted in chuck 11 and the chuck would be tightened thereon. The desired tool member would be detachably secured to the lower end of drive shaft 33 and the tool member would be secured to the object to be rotatably tightened. The activation of drill 10 Will initially cause shaft 13, clutch plate 15, clutch plate 31 and drive shaft 33 to be retated inasmuch as the balls 19 effect a connection be tween the plates 15 and 31 due to the fact that the lower portions of the balls are received by the recesses 41 and are maintained therein due to the fact that the compression of the spring means 27 is greater than the resistance being offered by the object being rotated. Pressure plate 21 and supporting plate 31 will also be rotated with the shaft 13. When the object being rotated has been tightened, the resistance offered thereby will overcome the resistance of the spring means 27 thereby causing the balls 19 to move out of engagement with the recesses 41 which is permitted by the compression of spring means 27 and the upward movement of pressure plate 21. The balls 19 are rotated with the clutch plate 15 and each time the balls 19 momentarily engage the recesses 41, an impact is imparted to clutch plate 39 and shaft 33 which securely tightens the object being rotated. When the clutch plates begin to slip with respect to each other, the electric drill may be deactivated.

The attachment may be also used to loosen a nut or the like by simply causing the tool means to be secured to the nut. Initially, the resistance of the nut may be greater than the force of the spring means 27, however the impact created by the successive momentary engagement of the balls 19 with the recesses 41 will create a sufficient impact to loosen the nut. As soon as the nut has been sufiiciently loosened so that the resistance thereof is less than the spring means 27, the balls 19 will reengage recesses 41 to effect a rigid interconnection of the clutch plates. The loosening of the nut by the procedure outlined above obviously requires an electric drill which is of the reversible type. It can also be seen that a variable speed electric drill would also be ideally suited for an attachment of this type.

It can be seen that the attachment permits an electric drill to be used as an impact tool means and that the electric drill may be used for other purposes when the attachment is not in use. The attachment is economical of manufacture and permits the selective clutch slippage to attain the desired tightening effect. Thus it can be seen that the device accomplishes at least all of its stated objectives.

I claim:

1. In an impact tool attachment for an electric drill having a rotatable chuck means, comprising,

a first drive shaft adapted to be secured at one end to the chuck means for rotation therewith,

a second drive shaft having a tool means at one end thereof,

and an impact clutch means operatively interconnecting the other ends of said first and second drive shafts, said impact clutch means including a flat, disc-shaped first clutch plate rigidly secured to said other end of said first drive shaft, a flat, disc-shaped second clutch plate rigidly secured to said other end of said second drive shaft and positioned adjacent said first clutch plate in a superimposed position with respect thereto, said first clutch plate having a plurality of spaced apart openings formed therein and extending completely therethrough, a ball movably mounted in each of said openings and having a diameter greater than the thickness of said first clutch plate, said second clutch plate having a plurality of recesses formed therein adapted to receive said balls, and a spring loaded pressure plate means on said first drive shaft urging said balls into said recesses,

said balls normally engaging said pressure plate on one side of said first clutch plate and normally engaging said recesses in said second cutch plate at the opposite side of said first clutch plate,

a supporting plate rotatably embracing said second drive shaft adjacent said second clutch plate between said second clutch plate and said one end of said second drive shaft, said supporting plate and said first clutch plate being rigidly interconnected, and a bearing means secured to said supporting plate and rotatably embracing said second drive shaft.

2. The attachment of claiml wherein said recesses each consist of a spherical indentation formed in said second clutch plate.

3. The attachment of claim 1 wherein said spring 7 loaded pressure plate means includes a plate positioned References Cited UNITED STATES PATENTS 1,657,274 1/1928 Niedhammer 17393.6 1,909,366 5/1933 Koza 17393.6 X 2,209,155 7/1940 Fagg 173 93.6 X 2,637,426 5/1953 Van Sittert 17393.6

DAVID H. BROWN, Primary Examiner Us. 01. X.R. 

